Agent orange is a pheno-oxy-herbicide that was used in the past to defoliate areas. The most notable usage was during the Vietnam War, when it was reportedly used to defoliate the forested areas of Vietnam. A component of the herbicide is the highly toxic dioxin, 2,3,7,8-TCDD, which can deposit in the adipose tissues of the body.

Symptoms are variable related to the concentration of the exposure. It has been reported that this dioxin was associated with malignancies. This is a large area of controversy. There are data to support the contention that high exposure to this chemical does cause malignancies in animal models. However, agent orange has not been found to have caused a significant increase in the risk of soft tissue sarcomas, non-hodgkins lymphoma, testicular, primary liver, nasopharyngeal or lung cancer. These are based on retrospective review studies performed on Vietnam War veterans compared to their non-military counterparts.